Sleep and wakeup signaling for ethernet

ABSTRACT

A first communication device generates an Operation, Administration, and Maintenance (OAM) frame that includes i) OAM message content and ii) an OAM frame header outside of the OAM message content, wherein generating the OAM frame comprises generating the OAM frame header to include information that signals one of i) a low power sleep (LPS) request, and ii) a wake-up request (WUR). The first communication device transmits the OAM frame to a second communication device via a communication medium to signal to the second communication device the one of i) the LPS request, and ii) the WUR.

CROSS REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent App. No.63/088,726, entitled “WUR/LPS Signal Definition for 1000BaseT1 TC10Operation,” filed on Oct. 7, 2020, the disclosure of which is herebyexpressly incorporated herein by reference in its entirety.

FIELD OF TECHNOLOGY

The present disclosure relates generally to communication technology,and more particularly to power saving techniques for devices thatcommunicate via a communication link.

BACKGROUND

Technical Committee 10 (TC10) of the OPEN Alliance, has proposedmechanisms for one device to request, via an automotive communicationlink, one or more other devices to transition to a low power mode (sleepmode), and to instruct, via the automotive communication link, one ormore other devices to transition to an active mode. For example, whenthe one device wants one or more other devices to transition to thesleep mode, the one device transmits a low power sleep (LPS) request viaa communication link connected with a switch, and the switch propagatesthe LPS request to the one or more other devices. Similarly, when theone device wants one or more other devices to transition to the activemode, the one device transmits a wake-up request (WUR) to the switch viathe communication link, and the switch propagates the WUR (or otherwiseprompts the one or more other devices to transition to the active mode,such as by transmitting a wake-up pulse (WUP)).

FIG. 1 is a diagram of an Operation, Administration, and Maintenance(OAM) frame 100 as defined by the Institute for Electrical andElectronics Engineers (IEEE) 802.3bp Standard. The OAM frame 100consists of 12 symbols (Symbol 0 through Symbol 11), each symbolconsisting of eight data bits (D7 through D0) and a parity bit D8.

The Symbol 0 includes an even parity bit, four reserved bits, a Ping RXbit, a Ping TX bit, and two signal-to-noise ratio (SNR) bits.

The reserved bits (D4 through D7) are set to zero.

The communication device that transmits the OAM frame 100 sets the PingTX bit and expects a link partner to echo the value of the Ping TX bitin another OAM frame transmitted by the link partner. The Ping RX bit isset to echo a Ping TX bit value in another OAM frame transmitted by thelink partner.

The two SNR bits are set by the communication device to indicate an SNRlevel experienced by the communication device.

The Symbol 1 includes an odd parity bit, an OAM Message Valid (Valid)bit, an OAM Message Toggle (Toggle) bit, an OAM Message Acknowledge(Ack) bit, an OAM Message Toggle Acknowledge (TogAck) bit, and four OAMMessage Number (Message_Number) bits.

The Valid bit is set to indicate whether the OAM frame 100 includes avalid OAM message.

The Toggle bit is used to ensure proper OAM message synchronizationbetween the communication device and the link partner. The Toggle bit inthe OAM frame 100 is set to an opposite value of a Toggle bit in apreviously transmitted OAM frame that included another OAM message onlyif the link partner acknowledged that the other OAM message wasreceived. Because the same OAM message may be repeatedly transmitted inmultiple OAM frames, the Toggle bit helps to delineate a first OAMmessage from a different second OAM message.

The Ack bit set by the communication device to let the link partner knowthat an OAM message sent by the link partner was successfully receivedand that the communication device is ready to accept a new OAM message.

The TogAck bit is set by the communication device to let the linkpartner know which OAM message is being acknowledged. The TogAck bit isset to the value of the Toggle bit of the OAM message that is beingacknowledged. The TogAck bit is valid only if Ack is set to 1.

The Message_Number bits are used to indicate a meaning of an eight byteOAM message that is included in the OAM frame 100. Because there arefour Message_Number bits, up to 16 different types of OAM messages maybe defined by a user. The values of the Message_Number bits areuser-defined and not specified by the IEEE 802.3bp Standard.

Symbol 2 through Symbol 9 include the OAM message and respective oddparity bits. OAM messages are user-defined and not specified by the IEEE802.3bp Standard.

Symbol 10 and Symbol 11 include a 16-bit cyclic redundancy check (CRC)field corresponding to a CRC generated using the 10 bytes included inSymbol 0 through Symbol 9 (i.e., not including the parity bits of Symbol0 through Symbol 9). Symbol 10 and Symbol 11 also include respective oddparity bits.

During normal operation, one respective symbol of the OAM frame 100 istransmitted within one respective Reed-Solomon (RS) frame. Inparticular, one respective symbol of the OAM frame 100 is included in anOAM field of the respective RS frame. The twelve symbols of the OAMframe 100 are included in twelve consecutive and respective RS frames.

During a low power idle (LPI) mode of operation that comprises aquiet/refresh cycle, one respective symbol of the OAM frame 100 isincluded in a respective refresh period, and the twelve symbols of theOAM frame 100 are included in twelve consecutive and respective refreshperiods.

The symbols of the OAM frame 100 are transmitted in order correspondingto the symbol numbers illustrated in FIG. 1 , i.e., Symbol 0 istransmitted first in time, then Symbol 1, etc., and Symbol 11 istransmitted last in time, according to an embodiment. The bits of eachsymbol of the OAM frame 100 are transmitted in order corresponding tothe bit numbers (D0, D1, etc.) illustrated in FIG. 1 , i.e., D0 istransmitted first in time, then D1, etc., and D8 is transmitted last intime, according to an embodiment.

It has been proposed to TC10 that the LPS request and the WUR request becommunicated within the OAM message content (e.g., at least in Symbol 2)of the OAM frame 100.

In 100Base-T1, the WUR and LPS signals are transmitted in gaps betweendata packets. In particular idle symbols transmitted in the gaps betweendata packets are encoded differently by selectively inverting a sequenceof bits before mapping the bits to a ternary symbol to indicate a WURsignal or an LPS signal.

SUMMARY

In an embodiment, a first communication device comprises: a physicallayer (PHY) processor comprising a transceiver, the PHY processor beingconfigured to perform PHY functions associated with a communication linkincluding transmitting first frames to a second communication device viaa communication medium corresponding to the communication link andreceiving second frames from the second communication device via thecommunication medium; and a controller configured to: generate anOperation, Administration, and Maintenance (OAM) frame that includes i)OAM message content and ii) an OAM frame header outside of the OAMmessage content, wherein generating the OAM frame comprises generatingthe OAM frame header to include information that signals one of i) a lowpower sleep (LPS) request, and ii) a wake-up request (WUR), and promptthe PHY processor to transmit the OAM frame to the second communicationdevice via the communication medium to signal to the secondcommunication device the one of i) the LPS request, and ii) the WUR.

In another embodiment, a method for communicating in a communicationnetwork includes: generating, at a first communication device, an OAMframe that includes i) OAM message content and ii) an OAM frame headeroutside of the OAM message content, wherein generating the OAM framecomprises generating the OAM frame header to include information thatsignals one of i) an LPS request, and ii) a WUR; and transmitting, bythe first communication device, the OAM frame to a second communicationdevice via a communication medium to signal to the second communicationdevice the one of i) the LPS request, and ii) the WUR.

In yet another embodiment, a first communication device comprises: a PHYprocessor comprising a transceiver, the PHY processor being configuredto perform PHY functions associated with a communication link includingtransmitting first frames to a second communication device via acommunication medium corresponding to the communication link andreceiving second frames from the second communication device via thecommunication medium; and a controller configured to: receive an OAMframe that was received by the PHY processor via the communicationmedium, the OAM frame having been transmitted to the first communicationdevice from a second communication device via the communication medium,the OAM frame including i) OAM message content and ii) an OAM frameheader outside of the OAM message content, and process the OAM frameheader to determine whether the OAM frame header includes informationthat signals to the first communication device one of i) an LPS request,and ii) a WUR.

In still another embodiment, a method for processing communications in acommunication network includes: receiving, at a first communicationdevice, an OAM frame from a second communication device via acommunication medium, the OAM frame including i) OAM message content andii) an OAM frame header outside of the OAM message content; andprocessing, at the first communication device, the OAM frame header todetermine whether the OAM frame header includes information that signalsto the first communication device one of i) an LPS request, and ii) aWUR.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an Operation, Administration, and Maintenance(OAM) frame 100 as defined by the Institute for Electrical andElectronics Engineers (IEEE) 802.3bp Standard.

FIG. 2 is a diagram of an example OAM frame that is useable to signal anLPS request and to signal a WUR request, according to some embodiments.

FIG. 3 is a simplified flow diagram of an example method for a firstcommunication device to signal to a second communication device arequest for the second communication device to transition to a low powermode, according to an embodiment.

FIG. 4 is a simplified flow diagram of an example method for a firstcommunication device to determine whether an OAM frame from a secondcommunication device (a link partner) includes a request for the firstcommunication device to transition to a low power mode, according to anembodiment.

FIG. 5 is a simplified flow diagram of an example method for a firstcommunication device to signal to a second communication device (a linkpartner) a request for the second communication device to wake up from alow power mode, according to an embodiment.

FIG. 6 is a simplified flow diagram of an example method for a firstcommunication device to determine whether an OAM frame from a secondcommunication device (a link partner) includes a request for the firstcommunication device to wake up from a low power mode, according to anembodiment.

FIG. 7 is a simplified block diagram of an example communication devicethat is configured to generate and transmit OAM frames having the formatillustrated in FIG. 2 , and to receive and process OAM frames having theformat illustrated in FIG. 2 , according to an embodiment.

FIG. 8 is a diagram of another example OAM frame that is useable tosignal an LPS request and to signal a WUR request, according to someembodiments.

FIG. 9 is a simplified block diagram of an example motor vehiclecommunication network having communication devices that use the exampleOAM frame of FIG. 2 or the example OAM frame of FIG. 8 (or anothersuitable OAM frame) to signal LPS requests and to signal WUR requests,according to some embodiments.

DETAILED DESCRIPTION

As discussed above, it has been proposed to TC10 that the LPS requestand the WUR request be communicated within the OAM message content(e.g., in Symbol 2) of the OAM frame 100 of FIG. 1 . However, includingthe LPS/WUR request in the OAM message content of the OAM frame 100results in an indefinite amount of delay in a link partner processingthe LPS/WUR request. For example, when an OAM message is completelyreceived at the link partner, the link partner places the OAM message ina queue. If the link partner is processing another OAM message when theLPS/WUR request is received, the LPS/WUR request will remain in thequeue indefinitely until the link partner is ready to process theLPS/WUR request. On the other hand, it is desirable that the linkpartner be required to acknowledge an LPS request within a defined timeperiod after a communication device transmits the LPS request so thatthe communication device can determine whether to abort the LPS request(e.g., the LPS request should be aborted if the link partner does notacknowledge the LPS request within the defined time period). If the linkpartner only processes the LPS request after an indefinite delay (e.g.,while the link partner is processing another OAM message), the linkpartner will not know an accurate receive time of the LPS request andthus cannot determine when the acknowledgment of the LPS request must betransmitted. Similarly, if the link partner only processes the LPSrequest after an indefinite delay (e.g., while the link partner isprocessing another OAM message), the link partner may not be ready totransmit the acknowledgment of the LPS request until after the definedtime period has expired.

Additionally, the IEEE 802.3bp Standard requires an OAM message to berepeatedly transmitted until the link partner acknowledges the OAMmessage. As a result, a communication device cannot transmit a new OAMmessage until a previous OAM message has been acknowledged by the linkpartner. If the LPS/WUR request is included in the OAM message content,there may be a delay between when a communication device determines thatan LPS/WUR request should be transmitted and when the communicationdevice is able to transmit the LPS/WUR request. For example, if the linkpartner has not yet acknowledged a previous OAM message, thecommunication device must wait to transmit the LPS/WUR request until thelink partner transmits the acknowledgment of the previous OAM message.

Further, as discussed above, OAM message numbers and OAM messages areuser-defined and are not specified by the IEEE 802.3bp Standard. Thus,if the LPS/WUR requests are defined as OAM messages having one or twocorresponding OAM message numbers, the LPS/WUR requests may beincompatible with some existing OAM implementations with user-definedOAM messages that conflict with the LPS/WUR requests.

Also, as mentioned above, in 100Base-T1, WUR and LPS signals aretransmitted as encoded idle symbols (i.e., selectively inverting asequence of bits in the idle symbol to indicate a WUR signal or an LPSsignal) transmitted in gaps between data packets. However, a descramblerat the link partner may have difficulty determining whether certain bitsare truly inverted in an idle symbol due to ambiguities in the idlesymbol from the standpoint of the descrambler.

In embodiments described below, bits in a first transmitted symbol of anOAM frame are used to signal WUR and LPS requests, as opposed to beingincluded only in the OAM message content. Because the WUR/LPS request isnot part of the OAM message content, a link partner receiving theWUR/LPS request can more accurately determine a receipt time of theWUR/LPS request (as compared to if the WUR/LPS request were included inthe OAM message content, as discussed above), at least in someembodiments. Additionally, because the WUR/LPS request is not part ofthe OAM message content, a communication device is not required to waitto transmit the WUR/LPS request until the link partner has acknowledgeda previous OAM message and thus the communication device can transmitthe WUR/LPS request with less delay (as compared to if the WUR/LPSrequest were included in the OAM message content, as discussed above),at least in some embodiments. Further, because the WUR/LPS request isnot part of the OAM message content, the WUR/LPS request signaling iscompatible with existing user-defined OAM messages, at least in someembodiments.

Further, because the WUR/LPS request is signaled within an OAM frame,problems with WUR/LPS signaling using encoded idle symbols (discussedabove) between data packets are avoided, at least in some embodiments.

FIG. 2 is a diagram of an example OAM frame 200 that is useable tosignal an LPS request and to signal a WUR request, according to someembodiments. The OAM frame 200 is similar to the OAM frame 100 of FIG. 1, and fields and bits similar to the OAM frame 100 of FIG. 1 are notdescribed in detail for purposes of brevity.

As illustrated in FIG. 2 , bits D8 through D0 are arranged in an ordercorresponding to the bit numbers D8 through D0, i.e., D0 is a first bitin the bit order, D1 is a second bit in the bit order, etc., and D8 is aninth bit in the bit order, according to an embodiment. The first bit(i.e., D0) is adjacent to the second bit (i.e., D1); the second bit isalso adjacent to the third bit (i.e., D2) and is between the first bitand the third bit; the third bit is also adjacent to the fourth bit(i.e., D3) and is between the second bit and the fourth bit; etc. Thus,bit D4 is fifth in the bit order and bit D5 is sixth in the bit order,according to an embodiment, with bit D4 adjacent to and between bits D3and D5, and with bit D5 adjacent to and between bits D4 and D6.

Symbol 0 includes i) an LPS bit 204 at location D4, and ii) a WUR bit208 at location D5, i.e., the LPS bit 204 is fifth in the bit order andthe WUR bit 208 is sixth in the bit order. In another embodiment, theLPS bit 204 is located at bit D5 and the WUR bit 208 is located at bitD4, i.e., the WUR bit 208 is fifth in the bit order and the LPS bit 204is sixth in the bit order. In various other embodiments, the LPS bit 204is one of bits D4-D7, and the WUR bit 208 is another one of the bitsD4-D7, i.e., the LPS bit 204 is one of fifth through eighth in the bitorder and the WUR bit 208 is another one of fifth through eighth in thebit order.

The LPS bit 204 is set to a first value to signal an LPS request and isset to a second value otherwise. In an embodiment, the first value isone and the second value is zero. In another embodiment, the first valueis zero and the second value is one.

The WUR bit 208 is set to a first value to signal a WUR request and isset to a second value otherwise. In an embodiment, the first value isone and the second value is zero. In another embodiment, the first valueis zero and the second value is one.

At least in some embodiments, the LPS bit 204 and the WUR bit 208 may beconsidered as a single multi-bit field in which i) a first value signalsan LPS request, ii) a second value signals a WUR request, iii) a thirdvalue indicates that neither an LPS request nor a WUR request is beingsignaled, and iv) and a fourth value is not permitted.

Although in the example OAM frame 200 of FIG. 2 , a single bit is usedto signal a WUR request and another single bit is used to signal an LPSrequest, in other embodiments multiple bits are used to signal one orboth of a WUR request and an LPS request. For example, in anotherembodiment, Symbol 0 includes i) a WUR field comprising two of bitsD4-D7 and ii) a LPS field comprising another two of bits D4-D7. In somesuch embodiments, a first value of the WUR field signals a WUR requestand the WUR field is otherwise set to other values; and a first value ofthe LPS field signals an LPS request and the LPS field is otherwise setto other values.

Although various embodiments were described above in which some or allof bits D4-D7 of Symbol 0 are used to signal WUR requests and LPSrequests, in other embodiments, other bits of Symbol 0 additionally oralternative are used to signal WUR requests and LPS requests. Forexample, some or all of the other fields of Symbol 0 (corresponding tobits D0-D3) are moved (e.g., to one or more of bits D4-D7) or omittedfrom the OAM frame 200, in some other embodiments.

Although various embodiments were described above in which bits ofSymbol 0 are used to signal WUR requests and LPS requests, in otherembodiments, bits of Symbol 1 additionally or alternative are used tosignal WUR requests and LPS requests. For example, one to four bits ofSymbol 1 are moved (e.g., to one or more of bits D4-D7) or omitted fromthe OAM frame 200, and such moved/omitted bits are used to signal WURrequests and LPS requests using techniques such as described above,according to some other embodiments.

Thus, more generally, bits outside of (or distinct from) the OAM messagecontent of an OAM frame are used to signal WUR requests and LPSrequests. In some embodiments, bits of Symbol 0 and/or Symbol 1 are usedto signal WUR requests and LPS requests, whereas Symbol 2 through Symbol9 include OAM message content and Symbol 10 and Symbol 11 include CRCcontent.

In an embodiment, Symbol 0 and Symbol 1 correspond to an OAM frameheader 212. As used herein, the term “OAM frame header” refers toinformation in an OAM frame that is outside of (or distinct from) OAMmessage content and that is transmitted prior to the OAM messagecontent. Thus, in some embodiments, bits in the OAM frame header areused to signal WUR requests and LPS requests.

Similar to the OAM frame 1 of FIG. 1 , the symbols of the OAM frame 200are transmitted in order corresponding to the symbol numbers illustratedin FIG. 2 (a first order in time), i.e., Symbol 0 is transmitted firstin time, then Symbol 1, etc., and Symbol 11 is transmitted last in time,according to an embodiment. The bits of each symbol of the OAM frame 200are transmitted in order corresponding to the bit numbers (D0, D1, etc.)illustrated in FIG. 2 (a second order in time), i.e., D0 is transmittedfirst in time, then D1, etc., and D8 is transmitted last in time,according to an embodiment. Thus, bit D4 is transmitted fifth (in time)and bit D5 is transmitted sixth (in time) among the bits D0-D8 of Symbol0. In another embodiment, the bits of Symbol 0 are scrambled accordingto a predetermined scrambling scheme prior to transmission, and thusbits D0-D8 are transmitted in an order in time that is different thanthe bit order illustrated in FIG. 2 . In other embodiments, at leastsome of the bits D0-D8 are transmitted in parallel using e.g., multiplelanes (e.g., multiple wired links) and/or using frequency shift keying(FSK) modulation, amplitude-shift keying (ASK) modulation, phase-shiftkeying (PSK) modulation, amplitude and phase-shift keying (APSK)modulation, orthogonal frequency division multiplexing (OFDM)modulation, etc.

FIG. 3 is a simplified flow diagram of an example method 300 for a firstcommunication device to signal an LPS request to a second communicationdevice (a link partner), according to an embodiment. In an embodiment,the LPS request corresponds to a request for the second communicationdevice to transition to a low power mode. In another embodiment, thesecond communication device is a switch that propagates the LPS requestto one or more third communication devices, and the LPS requestcorresponds to a request for the one or more third communication devicesto transition to the low power mode.

The method 300 is utilized in connection with an OAM frame that includesi) OAM message content, and ii) other information outside of (ordistinct from) the OAM message content, such as header information,trailer information, etc., according to some embodiments. For example,the method 300 is utilized in connection with an OAM frame having astructure as described above with reference to FIG. 2 , in someembodiments, and is described with reference to FIG. 2 for explanatorypurposes. In other embodiments, the method 300 is utilized in connectionwith an OAM frame having another suitable format.

At block 304, the first communication device generates a first OAM framehaving i) OAM message content, and ii) an LPS request indicator locatedwithin the OAM frame and outside of the OAM message content. In anembodiment, generating the first OAM frame at block 304 comprisesgenerating an OAM frame having a format as illustrated in FIG. 2 , withthe LPS bit 204 set to indicate an LPS request. In an embodiment,generating the first OAM frame at block 304 comprises generating an OAMframe having an LPS field within Symbol 0 set to indicate an LPSrequest.

At block 308, the first communication device transmits, via acommunication link, the first OAM frame generated at block 304 to thelink partner, according to an embodiment.

Some embodiments of the method 300 involve a handshake procedure inwhich the intended recipient of the LPS request, in response toreceiving the LPS request within the first OAM frame, transmits asubsequent OAM frame to the first communication device when the intendedrecipient decides to transition to the low power mode. Thus, at block312, the first communication device receives, via the communicationlink, a subsequent OAM frame that was transmitted by the link partner(or the intended recipient of the first OAM frame). In an embodiment,the subsequent OAM frame has a same general format as the first OAMframe generated at block 304. In some embodiments, the subsequent OAMframe has a structure as described above with reference to FIG. 2 .

At block 316, the first communication device determines whether thesubsequent OAM frame includes one or more bit errors using CRCinformation in the subsequent OAM frame. In embodiments in which thesubsequent OAM frame has a structure as described above with referenceto FIG. 2 , the first communication device generates a CRC result usingSymbol 0 through Symbol 9, and then compares the CRC result to a CRCvalue included in Symbol 10 and Symbol 11. If the first communicationdevice determines that the CRC result equals the CRC value included inSymbol 10 and Symbol 11, the flow proceeds to block 320.

At block 320, the first communication device determines whether thesubsequent OAM frame includes an LPS request indicator. The subsequentOAM frame includes OAM message content, and block 320 includesdetermining whether the subsequent OAM frame includes an LPS requestindicator located within the subsequent OAM frame and outside of the OAMmessage content. In an embodiment, determining whether the subsequentOAM frame includes the LPS request indicator at block 320 comprisesdetermining whether the LPS bit 204 is set to indicate an LPS request.In an embodiment, determining whether the subsequent OAM frame includesthe LPS request indicator at block 320 comprises determining whether thesubsequent OAM frame includes an LPS field within Symbol 0 set toindicate an LPS request.

If the first communication device determines that the subsequent OAMframe includes the LPS request indicator, the flow proceeds to block324. At block 324, the first communication device determines that an LPShandshake was completed. Completion of the LPS handshake helps the firstcommunication device to confirm that the intended recipient willtransition to the low power mode in response to the first OAM frame,according to some embodiments.

Referring again to block 316, if the first communication devicedetermines that the CRC result does not equal the CRC value included inSymbol 10 and Symbol 11, the flow proceeds to block 328. At block 328,the first communication device determines whether a timeout period haselapsed. For example, the first communication device starts a timer inconnection with transmitting the first OAM frame at block 308, anddetermines whether the timer expired at block 328.

In response to determining that the timeout period has not elapsed, theflow returns to block 312 to receive a next OAM frame. For example, insome embodiments, the second communication device transmits one or moreother OAM frames before transmitting an OAM frame with an LPS indicator.Thus, the first communication device may evaluate one or more other OAMframes from the second communication device at blocks 316 and 320 priorto detecting an OAM frame that includes an LPS indicator.

Referring again to block 320, if the first communication devicedetermines that the subsequent OAM frame does not include an LPS requestindicator, the flow proceeds to block 328, at which the firstcommunication device determines whether the timeout period elapsed, asdiscussed above.

In some embodiments that use an OAM frame structure in which an LPSrequest field is included in Symbol 0 and Symbol 0 also includes aparity bit, the method 300 further comprises checking the parity bit ofSymbol 0 of the subsequent OAM frame to determine if Symbol 0 includes abit error. In response to determining, using the parity bit, that Symbol0 includes a bit error, the flow of the method 300 proceeds to block328. On the other hand, in response to determining, using the paritybit, that Symbol 0 does not include a bit error, further processing ofthe subsequent OAM frame proceeds.

In some other embodiments, the method 300 does not utilize a handshakeprocedure such as described above and omits blocks 312, 316, 320, 324,and 328.

In other embodiments, other suitable modifications to the flowillustrated in FIG. 3 are made, such as omitting one or more blocks,adding additional blocks, etc. As an example, block 316 is omitted insome embodiments. As another example, one or more additional blockscorresponding to additional processing of the subsequent OAM frame areincluded in other embodiments.

FIG. 4 is a simplified flow diagram of an example method 400 for a firstcommunication device to determine whether an OAM frame from a secondcommunication device (a link partner) includes a request for the firstcommunication device to transition to a low power mode, according to anembodiment. The method 400 is utilized in connection with an OAM framethat includes i) OAM message content, and ii) other information outsideof (or distinct from) the OAM message content, such as headerinformation, trailer information, etc., according to some embodiments.For example, the method 400 is utilized in connection with an OAM framehaving a structure as described above with reference to FIG. 2 , in someembodiments, and is described with reference to FIG. 2 for explanatorypurposes. In other embodiments, the method 400 is utilized in connectionwith an OAM frame having another suitable format.

At block 404, the first communication device receives, via acommunication link, a first OAM frame that was transmitted by the linkpartner. In an embodiment, the first OAM frame received at block 404 hasa structure as described above with reference to FIG. 2 . In otherembodiments, the first OAM frame has another suitable structure.

At block 408, the first communication device determines whether thefirst OAM frame includes one or more bit errors using CRC information inthe first OAM frame. In embodiments in which the first OAM frame has astructure as described above with reference to FIG. 2 , the firstcommunication device generates a CRC result using Symbol 0 throughSymbol 9, and then compares the CRC result to a CRC value included inSymbol 10 and Symbol 11. If the first communication device determinesthat the CRC result does not equal the CRC value included in Symbol 10and Symbol 11, the flow ends. On the other hand, if the firstcommunication device determines that the CRC result equals the CRC valueincluded in Symbol 10 and Symbol 11, the flow proceeds to block 412.

At block 412, the first communication device determines whether thefirst OAM frame includes an LPS request indicator. As discussed above,the first OAM frame includes OAM message content, and block 412 includesdetermining whether the first OAM frame includes an LPS requestindicator located within the first OAM frame and outside of the OAMmessage content. In an embodiment, determining whether the first OAMframe includes the LPS request indicator at block 412 comprisesdetermining whether the LPS bit 204 is set to indicate an LPS request.In an embodiment, determining whether the first OAM frame includes theLPS request indicator at block 412 comprises determining whether thefirst OAM frame includes an LPS field within Symbol 0 set to indicate anLPS request.

If the first communication device determines at block 412 that the firstOAM frame does not include the LPS request indicator, the flow proceedsto block 416. At block 416, the first communication device determinesthat the first OAM frame does not signal an LPS request. When the firstOAM frame does not signal an LPS request, the first communication devicemay further process the first OAM frame for purposes unrelated to LPSrequests, according to an embodiment.

On the other hand, if the first communication device determines at block412 that the first OAM frame includes the LPS request indicator, thefirst communication device determines that the first OAM frame includesan LPS request at block 420.

At block 424, the first communication device determines whether thefirst communication device will transition to the low power mode inresponse to the LPS request in the first OAM frame. In response to thefirst communication device determining at block 424 that the firstcommunication device will not transition to the low power mode inresponse to the LPS request in the first OAM frame, the flow ends.

On the other hand, in response to the first communication devicedetermining at block 424 that the first communication device willtransition to the low power mode in response to the LPS request in thefirst OAM frame, the flow proceeds to block 428. At block 428, the firstcommunication device generates a second OAM frame having i) OAM messagecontent, and ii) an LPS request indicator located within the OAM frameand outside of the OAM message content. In an embodiment, generating thesecond OAM frame at block 428 comprises generating an OAM frame having aformat as illustrated in FIG. 2 , with the LPS bit 204 set to indicatean LPS request. In an embodiment, generating the second OAM frame atblock 428 comprises generating an OAM frame having an LPS field withinSymbol 0 set to indicate an LPS request.

At block 432, the first communication device transmits, via thecommunication link, the second OAM frame generated at block 428 to thelink partner to signal that the first communication device willtransition to the low power mode. Transmitting the second OAM frame atblock 432 corresponds to a handshake procedure, such as described withreference to FIG. 3 , in which the first communication device, inresponse to receiving the LPS request within the first OAM frame and inresponse to determining that the first communication device willtransition to the low power mode, transmits the second OAM frame to thelink partner to signal that the first communication device willtransition to the low power mode in response to receiving the first OAMframe.

In some embodiments, the first communication device transmits one ormore other OAM frames between receiving the first OAM frame andtransmitting the second OAM frame.

In some embodiments that use an OAM frame structure in which an LPSrequest field is included in Symbol 0 and Symbol 0 also includes aparity bit, the method 400 further comprises checking the parity bit ofSymbol 0 of the first OAM frame to determine if Symbol 0 includes a biterror. In response to determining, using the parity bit, that Symbol 0includes a bit error, the flow of the method 400 ends. On the otherhand, in response to determining, using the parity bit, that Symbol 0 ofthe first OAM frame does not include a bit error, further processing ofthe first OAM frame proceeds.

In some other embodiments, the method 400 does not utilize a handshakeprocedure such as described above and omits blocks 428 and 432.

In other embodiments, other suitable modifications to the flowillustrated in FIG. 4 are made, such as omitting one or more blocks,adding additional blocks, etc. As just one example, block 408 is omittedin another embodiment. As another example, one or more blockscorresponding to additional processing of the first OAM frame are addedin some embodiments. As yet another example, the method 400 furthercomprises transitioning at least some circuitry of the firstcommunication device to the low power mode in response to (at leastpartially) determining at block 424 that the first communication devicewill enter the low power mode, according to another embodiment.

FIG. 5 is a simplified flow diagram of an example method 500 for a firstcommunication device to prompt a second communication device (a linkpartner) to propagate a request for one or more third communicationdevices to wake up from a low power mode, according to an embodiment.The method 500 is utilized in connection with an OAM frame that includesi) OAM message content, and ii) other information outside of the OAMmessage content, such as header information, trailer information, etc.,according to some embodiments. For example, the method 500 is utilizedin connection with an OAM frame having a structure as described abovewith reference to FIG. 2 , in some embodiments, and is described withreference to FIG. 2 for explanatory purposes. In other embodiments, themethod 500 is utilized in connection with an OAM frame having anothersuitable format.

At block 504, the first communication device generates an OAM framehaving i) OAM message content, and ii) a WUR request indicator locatedwithin the OAM frame and outside of the OAM message content. In anembodiment, generating the OAM frame at block 504 comprises generatingan OAM frame having a format as illustrated in FIG. 2 , with the WUR bit208 set to indicate a WUR request. In an embodiment, generating the OAMframe at block 504 comprises generating an OAM frame having a WUR fieldwithin Symbol 0 set to indicate a WUR request.

At block 508, the first communication device transmits, via acommunication link, the OAM frame generated at block 504 to the linkpartner to prompt the link partner to propagate a request for one ormore third communication devices to wake up from a low power mode ofoperation, according to an embodiment.

FIG. 6 is a simplified flow diagram of an example method 600 for a firstcommunication device to determine whether an OAM frame from a secondcommunication device (a link partner) includes a request for the firstcommunication device to propagate a request for one or more thirdcommunication devices to wake up from a low power mode, according to anembodiment. The method 600 is utilized in connection with an OAM framethat includes i) OAM message content, and ii) other information outsideof the OAM message content, such as header information, trailerinformation, etc., according to some embodiments. For example, themethod 600 is utilized in connection with an OAM frame having astructure as described above with reference to FIG. 2 , in someembodiments, and is described with reference to FIG. 2 for explanatorypurposes. In other embodiments, the method 600 is utilized in connectionwith an OAM frame having another suitable format.

At block 604, the first communication device receives, via acommunication link, an OAM frame that was transmitted by the linkpartner. In an embodiment, the OAM frame received at block 604 has astructure as described above with reference to FIG. 2 . In otherembodiments, the OAM frame has another suitable structure.

At block 608, the first communication device determines whether the OAMframe includes one or more bit errors using CRC information in the OAMframe. In embodiments in which the OAM frame has a structure asdescribed above with reference to FIG. 2 , the first communicationdevice generates a CRC result using Symbol 0 through Symbol 9, and thencompares the CRC result to a CRC value included in Symbol 10 and Symbol11. If the first communication device determines that the CRC resultdoes not equal the CRC value included in Symbol 10 and Symbol 11, theflow ends. On the other hand, if the first communication devicedetermines that the CRC result equals the CRC value included in Symbol10 and Symbol 11, the flow proceeds to block 612.

At block 612, the first communication device determines whether the OAMframe includes a WUR request indicator. As discussed above, the OAMframe includes OAM message content, and block 612 includes determiningwhether the OAM frame includes a WUR request indicator located withinthe OAM frame and outside of the OAM message content. In an embodiment,determining whether the OAM frame includes the WUR request indicator atblock 612 comprises determining whether the WUR bit 208 is set toindicate a WUR request. In an embodiment, determining whether the OAMframe includes the WUR request indicator at block 612 comprisesdetermining whether the OAM frame includes a WUR field within Symbol 0set to indicate a WUR request.

If the first communication device determines at block 612 that the OAMframe does not include the WUR request indicator, the flow proceeds toblock 616. At block 616, the first communication device determines thatthe OAM frame does not signal a WUR request. On the other hand, if thefirst communication device determines at block 612 that the OAM frameincludes the WUR request indicator, the flow proceeds to block 620. Atblock 620, the first communication device determines that the OAM frameincludes a WUR request.

In some embodiments that use an OAM frame structure in which a WURrequest field is included in Symbol 0 and Symbol 0 also includes aparity bit, the method 600 further comprises checking the parity bit ofSymbol 0 of the OAM frame to determine if Symbol 0 includes a bit error.In response to determining, using the parity bit, that Symbol 0 includesa bit error, the flow of the method 600 ends. On the other hand, inresponse to determining, using the parity bit, that Symbol 0 of the OAMframe does not include a bit error, further processing of the OAM frameproceeds.

In other embodiments, other suitable modifications to the flowillustrated in FIG. 6 are made, such as omitting one or more blocks,adding additional blocks, etc. As just one example, block 608 is omittedin another embodiment. As another example, one or more blockscorresponding to additional processing of the OAM frame are added insome embodiments. As yet another example, the method 600 furthercomprises propagating a request for one or more third communicationdevices to transition to an active mode in response to (at leastpartially) determining at block 620 that the OAM frame signals a WURrequest, according to another embodiment.

FIG. 7 is a block diagram of an example communication device 700 that isconfigured to generate and transmit OAM frames such as described above,and to receive and process OAM frames such as described above, accordingto an embodiment. The communication device 700 includes at least a mediaaccess control (MAC) processing device 710 and a physical layer (PHY)processing device 720. In some embodiments, the MAC processing device710 and the PHY processing device 720 are compliant with the IEEE 802.3Ethernet Standard, except as otherwise disclosed below. In otherembodiments, the MAC processing device 710 and the PHY processing device720 are compliant with another suitable communication protocol.

The MAC processing device 710 is configured to perform MAC layerfunctions associated with a communication protocol such as thecommunication protocol defined by the IEEE 802.3 Ethernet Standard oranother suitable communication protocol. Similarly, the PHY processingdevice 720 is configured to perform PHY functions associated with acommunication protocol such as the communication protocol defined by theIEEE 802.3 Ethernet Standard (except as otherwise disclosed below) oranother suitable communication protocol.

In an embodiment the MAC processing device 710 comprises a processor(not shown) and a memory (not shown) coupled to the processor, where theprocessor is configured to execute machine readable instructions storedin the memory. In an embodiment, the memory stores machine readableinstructions that, when executed by the processor, cause the processorto perform MAC layer functions associated with a communication protocolsuch as the communication protocol defined by the IEEE 802.3 EthernetStandard or another suitable communication protocol.

In another embodiment the MAC processing device 710 additionally oralternatively comprises a hardware state machine (not shown) configuredto perform MAC layer functions associated with a communication protocolsuch as the communication protocol defined by the IEEE 802.3 EthernetStandard or another suitable communication protocol.

The MAC processing device 710 is communicatively coupled to the PHYprocessing device 720 via a communication interface 730 such as a 10Gigabit Media Independent Interface (XGMII). In other embodiments, theMAC processing device 710 is communicatively coupled to the PHYprocessing device 720 via another suitable communication interface suchas another suitable media independent interface (e.g., the reducedmedia-independent interface (RMII), the Gigabit Media IndependentInterface (GMII), the reduced gigabit media-independent interface(RGMII), the serial gigabit media-independent interface (SGMII), thehigh serial gigabit media-independent interface (HSGMII), the quadserial gigabit media-independent interface (QSGMII), etc.), according tosome embodiments.

In an embodiment, the MAC processing device 710 provides, via theinterface 730, data to the PHY processing device 720 for transmissionvia a suitable communication medium 735 such as a wired, optical, orwireless communication medium. In an illustrative embodiment, thecommunication medium 735 comprises a single twisted pair. In anotherillustrative embodiment, the communication medium 735 comprises multipletwisted pairs. In various embodiments, the communication medium 735 isconfigured for communication at one or more suitable bit rates such asone or more of 100 Megabits per second (Mbps), 1 Gigabit per second(Gbps), 2.5 Gbps, 5 Gbps, 10 Gbps, 25 Gbps, 100 Gbps, etc.

In response to receiving the data from the MAC processing device 710,the PHY processing device 720 encodes, scrambles, and modulates the datato generate a transmission signal for transmitting the data via thecommunication medium 735.

In an embodiment, the PHY processing device 720 also receives a receivesignal via the communication medium, and demodulates, de-scrambles, anddecodes data in the receive signal to generate received data.Additionally, the PHY processing device 720 provides at least some ofthe received data to the MAC processing device 710 via the interface730.

The PHY processing device 720 includes one or more encoder devices (notshown), a scrambler device (not shown), and a modulator (not shown) forencoding, scrambling, and modulating data as part of generating atransmission signal, according to an embodiment. The PHY processingdevice 720 also includes a demodulator (not shown), a de-scramblerdevice (not shown), and one or more decoder devices (not shown) fordemodulating, de-scrambling, and decoding as part of generating thereceived data, according to an embodiment. In some embodiments, the PHYprocessing device 720 also includes an analog to digital converter(hereinafter “ADC”, not shown) that converts an analog signal receivedvia the communication medium to a digital signal. In some embodiments,the PHY processing device 720 also includes a digital signal processor(hereinafter “DSP”, not shown) that processes the digital signal togenerate a signal corresponding to modulation symbols that are thendemodulated by the demodulator (not shown).

In an embodiment, the PHY processing device 720 comprises a hardwarestate machine (not shown) in which at least some states of the hardwarestate machine generally correspond to at least some of the variousoperating states and/or modes of the PHY processing device 720. Thehardware state machine is configured to generate control signals thatcontrol operation of the PHY processing device 720 according to variousoperating states and/or modes, and to transition between states of thehardware state machine in response to receiving signals and/orinformation.

In another embodiment, the PHY processing device 720 comprises aprocessor that executes machine readable instructions that causes theprocessor to implement a state machine similar to the hardware statemachine described above.

In an embodiment, communication device 700 is configured to operateaccording to a suitable communication protocol such as a communicationprotocol defined by the IEEE 802.3bp Standard, a communication protocoldefined by the IEEE 802.3bw Standard, a communication protocol definedby the IEEE 802.3ch Standard, a communication protocol defined by theIEEE 802.3ck Standard (now under development), a communication protocoldefined by the IEEE 802.3cy Standard (now under development), acommunication protocol defined by the IEEE 802.3cz Standard (now underdevelopment), etc.

The PHY processing device 720 comprises an OAM frame generator 740. TheOAM frame generator 740 is configured to generate OAM frames such asdescribed above for transmission to a link partner via the communicationmedium.

The communication device 700 also includes an OAM controller 760communicatively coupled to the PHY processing device 720 via aninterface 780 (e.g., a serial management interface (SMI) or anothersuitable interface) that is separate from the interface 730, accordingto an embodiment. The OAM controller 760 is configured to prompt the OAMframe generator 740 to generate OAM frames such as described above fortransmission to a link partner via the communication medium; and the OAMcontroller 760 is also configured to process OAM frames such asdescribed above that are received from the PHY processing device 720,the received OAM frames having been transmitted by the link partner viathe communication medium 735. For instance, in various embodiments, theOAM controller 760 is configured to prompt the OAM frame generator 740to generate an OAM frame having the format illustrated in FIG. 2 fortransmission to a link partner, and to process an OAM frame having theformat illustrated in FIG. 2 when the OAM frame is received from thelink partner.

In various embodiments, the communication device 700 is configured toperform one of, or any suitable combination of two or more of, themethods discussed above with reference to FIGS. 3-6 . In variousembodiments, the OAM controller 760 is configured to perform (alone orin conjunction with the OAM frame generator 740, the PHY processingdevice 720, the MAC processing device 710, and/or the interface 780) themethods discussed above with reference to FIGS. 3-6 .

In other embodiments, the OAM controller 760 is included in the PHYprocessing device 720 and the interface 780 is omitted. In otherembodiments, the OAM frame generator 740 is external to the PHYprocessing device 720, and OAM frames generated by the OAM framegenerator 740 are provided to the PHY processing device 720 via theinterface 780. In other embodiments, the OAM controller 760 is includedin the MAC processing device 710 and the interface 780 is omitted; forexample, the OAM controller 760 is configured to signal the OAM framegenerator 740, via the interface 730, to generate OAM frames such asdescribed above, and the OAM controller 760 is also configured toreceive OAM frames such as described above from the PHY processingdevice 720 via the interface 730.

In another embodiment, the PHY processing device 720 includes a LPS/WURdetector (not shown) that is configured to i) determine whether an OAMframe received via the communication medium 735 includes an LPS signalor a WUR signal, and ii) signal to the OAM controller 760, via theinterface 780, whether the OAM frame includes an LPS signal or a WURsignal.

FIG. 8 is a diagram of another example OAM frame 800 that is useable tosignal an LPS request and to signal a WUR request, according to someembodiments. The OAM frame 800 is similar to an OAM frame defined by theIEEE 802.3ch Standard. In various embodiments, the OAM frame 800 is usedin conjunction with the method 300 of FIG. 3 , the method 400 of FIG. 4, the method 500 of FIG. 5 , the method 600 of FIG. 6 , and/or thecommunication device 700 of FIG. 7 .

The OAM frame 800 is similar to the OAM frame 100 of FIG. 1 and to theOAM frame 200 of FIG. 2 , and some fields and bits similar to the OAMframe 100 of FIG. 1 and/or the OAM frame 200 of FIG. 2 are not describedin detail for purposes of brevity.

The OAM frame 800 consists of 16 symbols (Symbol 0 through Symbol 15),each symbol consisting of ten data bits, D9 through D0. In Symbol 0through Symbol 13, the data bit D8 is set to values as indicated in FIG.8 , and data bit D9 is reserved.

Symbol 2 through Symbol 13 include the OAM message (within data bits D7through D0). OAM messages are user-defined and not specified by the IEEE802.3ch Standard.

Symbol 14 and Symbol 15 include Reed-Solomon parity informationgenerated according to a Reed-Solomon error correcting code using atleast the 12 bytes included in Symbol 2 through Symbol 13.

As illustrated in FIG. 8 , bits D9 through D0 are arranged in an ordercorresponding to the bit numbers D9 through D0, i.e., D0 is a first bitin the bit order, D1 is a second bit in the bit order, etc., and D9 is atenth bit in the bit order, according to an embodiment. The first bit(i.e., D0) is adjacent to the second bit (i.e., D1); the second bit isalso adjacent to the third bit (i.e., D2) and is between the first bitand the third bit; the third bit is also adjacent to the fourth bit(i.e., D3) and is between the second bit and the fourth bit; etc. Thus,bit D4 is fifth in the bit order and bit D5 is sixth in the bit order,according to an embodiment, with bit D4 adjacent to and between bits D3and D5, and with bit D5 adjacent to and between bits D4 and D6.

Symbol 0 includes i) an LPS bit 804 at location D4, and ii) a WUR bit808 at location D5, i.e., the LPS bit 804 is fifth in the bit order andthe WUR bit 808 is sixth in the bit order. In another embodiment, theLPS bit 804 is located at bit D5 and the WUR bit 808 is located at bitD4, i.e., the WUR bit 808 is fifth in the bit order and the LPS bit 804is sixth in the bit order. In various other embodiments, the LPS bit 804is one of bits D4-D7, and the WUR bit 808 is another one of the bitsD4-D7, i.e., the LPS bit 804 is one of fifth through eighth in the bitorder and the WUR bit 808 is another one of fifth through eighth in thebit order.

The LPS bit 804 is set to a first value to signal an LPS request and isset to a second value otherwise. In an embodiment, the first value isone and the second value is zero. In another embodiment, the first valueis zero and the second value is one.

The WUR bit 808 is set to a first value to signal a WUR request and isset to a second value otherwise. In an embodiment, the first value isone and the second value is zero. In another embodiment, the first valueis zero and the second value is one.

At least in some embodiments, the LPS bit 804 and the WUR bit 808 may beconsidered as a single multi-bit field in which i) a first value signalsan LPS request, ii) a second value signals a WUR request, iii) a thirdvalue indicates that neither an LPS request nor a WUR request is beingsignaled, and iv) and a fourth value is not permitted.

Although in the example OAM frame 800 of FIG. 8 , a single bit is usedto signal a WUR request and another single bit is used to signal an LPSrequest, in other embodiments multiple bits are used to signal one orboth of a WUR request and an LPS request. For example, in anotherembodiment, Symbol 0 includes i) a WUR field comprising two of bitsD4-D7 and ii) a LPS field comprising another two of bits D4-D7. In somesuch embodiments, a first value of the WUR field signals a WUR requestand the WUR field is otherwise set to other values; and a first value ofthe LPS field signals an LPS request and the LPS field is otherwise setto other values.

Although various embodiments were described above in which some or allof bits D4-D7 of Symbol 0 are used to signal WUR requests and LPSrequests, in other embodiments, other bits of Symbol 0 additionally oralternative are used to signal WUR requests and LPS requests. Forexample, some or all of the other fields of Symbol 0 (corresponding tobits D0-D3) are moved (e.g., to one or more of bits D4-D7) or omittedfrom the OAM frame 800, in some other embodiments.

Although various embodiments were described above in which bits ofSymbol 0 are used to signal WUR requests and LPS requests, in otherembodiments, bits of Symbol 1 additionally or alternative are used tosignal WUR requests and LPS requests. For example, one to four bits ofSymbol 1 are moved (e.g., to one or more of bits D4-D7) or omitted fromthe OAM frame 800, and such moved/omitted bits are used to signal WURrequests and LPS requests using techniques such as described above,according to some other embodiments.

Thus, more generally, bits outside of the OAM message content of an OAMframe are used to signal WUR requests and LPS requests. In someembodiments, bits of Symbol 0 and/or Symbol 1 are used to signal WURrequests and LPS requests, whereas Symbol 2 through Symbol 13 includeOAM message content, and Symbol 14 and Symbol 15 include errorcorrection code (e.g., Reed-Solomon code, or another suitable errorcorrection code) parity content. In another embodiment, Symbol 14 andSymbol 15 include error detection code (e.g., CRC, or another suitableerror detection code) parity content.

In an embodiment, Symbol 0 and Symbol 1 correspond to an OAM frameheader 812. As used herein, the term “OAM frame header” refers toinformation in an OAM frame that is outside of OAM message content andthat is transmitted prior to the OAM message content. Thus, in someembodiments, bits in the OAM frame header are used to signal WURrequests and LPS requests.

Similar to the OAM frame 1 of FIG. 1 , the symbols of the OAM frame 800are transmitted in order corresponding to the symbol numbers illustratedin FIG. 8 (a first order in time), i.e., Symbol 0 is transmitted firstin time, then Symbol 1, etc., and Symbol 15 is transmitted last in time,according to an embodiment. The bits of each symbol of the OAM frame 800are transmitted in order corresponding to the bit numbers (D0, D1, etc.)illustrated in FIG. 8 (a second order in time), i.e., D0 is transmittedfirst in time, then D1, etc., and D9 is transmitted last in time,according to an embodiment. Thus, bit D4 is transmitted fifth (in time)and bit D5 is transmitted sixth (in time) among the bits D0-D9 of Symbol0. In another embodiment, the bits of Symbol 0 are scrambled accordingto a predetermined scrambling scheme prior to transmission, and thusbits D0-D9 are transmitted in an order in time that is different thanthe bit order illustrated in FIG. 8 . In other embodiments, at leastsome of the bits D0-D9 are transmitted in parallel using e.g., multiplelanes (e.g., multiple wired links), and/or using FSK modulation, ASKmodulation, PSK modulation, APSK modulation, OFDM modulation, etc.

FIG. 9 is a simplified block diagram of an example motor vehiclecommunication network 900, according to an embodiment. Various methods,apparatuses, and OAM frames discussed above are implemented in (and/orused in conjunction with) the motor vehicle communication network 900,according to various embodiments.

The motor vehicle communication network 900 includes a controller 904,an Ethernet switch 908, an Ethernet switch 912, and a rear-facing camerasubsystem 916. The controller 904 is communicatively coupled to theEthernet switch 908 via an Ethernet link 924. The Ethernet switch 908 iscommunicatively coupled to the Ethernet switch 912 via an Ethernet link928. The rear-facing camera subsystem 916 is communicatively coupled tothe Ethernet switch 912 via an Ethernet link 932.

The controller 904 comprises a processor (not shown) and a memory (notshown) communicatively coupled to the processor, where the processorexecutes machine readable instructions stored in the memory. Therear-facing camera subsystem 916 includes one or more cameras (notshown). The rear-facing camera subsystem 916 optionally includes aprocessor (not shown) and a memory (not shown) communicatively coupledto the processor, where the processor executes machine readableinstructions stored in the memory.

Each of the controller 904, the Ethernet switch 908, the Ethernet switch912, and the rear-facing camera subsystem 916 includes a respective OAMframe generator 740 and a respective OAM controller 760 discussed abovewith reference to FIG. 7 , according to an embodiment. In anotherembodiment, each of the controller 904, the Ethernet switch 908, theEthernet switch 912, and the rear-facing camera subsystem 916additionally includes a respective LPS/WUR detector (not shown)discussed above with reference to FIG. 7 . In another embodiment, eachof the controller 904, the Ethernet switch 908, the Ethernet switch 912,and the rear-facing camera subsystem 916 additionally includes arespective communication device 700 discussed above with reference toFIG. 7 .

As an illustrative example, the Ethernet switch 912 may prompt therear-facing camera subsystem 916 to go into a low power mode bytransmitting an OAM frame with an indicator of an LPS request (such asdescribed above) to the rear-facing camera subsystem 916 via theEthernet link 932. For instance, the Ethernet switch 912 may transmitthe OAM frame with the indicator of the LPS request via the Ethernetlink 932 in response to detecting a lack of activity on the Ethernetlink 932 for a certain length of time. In response to receiving the OAMframe with the indicator of the LPS request via the Ethernet link 932,the rear-facing camera subsystem 916 may transition to a low power mode.

As another illustrative example in which the Ethernet switch 912 and therear-facing camera subsystem 916 are already in the low power mode, thecontroller 904 may cause the Ethernet switch 912 and the rear-facingcamera subsystem 916 to transition to an active mode by transmitting anOAM frame with an indicator of a WUR (such as described above) to theEthernet switch 908 via the Ethernet link 924. For example, thecontroller 904 may determine that a gear selector has been put into adrive gear, a reverse gear, etc., and thus determine that devices in theautomotive network 900 (e.g., the Ethernet switch 912 and therear-facing camera subsystem 916) should transition to the active mode.

In response to receiving the OAM frame with the indicator of the WUR viathe Ethernet link 924, the Ethernet switch 908 transmits a wake-uppulses (WUPs) via the Ethernet link 928 (i.e., the Ethernet switch 908propagates the wake-up request from the controller 904) to prompt theEthernet switch 912 to transition to the active mode. In response toreceiving the WUPs via the Ethernet link 928, the Ethernet switch 912transitions to the active mode and transmits WUPs via the Ethernet link932 to prompt the rear-facing camera subsystem 916 to transition to theactive mode. In response to receiving the WUPs via the Ethernet link932, the rear-facing camera subsystem 916 transitions to the activemode.

Embodiment 1: A first communication device, comprising: a physical layer(PHY) processor comprising a transceiver, the PHY processor beingconfigured to perform PHY functions associated with a communication linkincluding transmitting first frames to a second communication device viaa communication medium corresponding to the communication link andreceiving second frames from the second communication device via thecommunication medium; and a controller configured to: generate anOperation, Administration, and Maintenance (OAM) frame that includes i)OAM message content and ii) an OAM frame header outside of the OAMmessage content, wherein generating the OAM frame comprises generatingthe OAM frame header to include information that signals one of i) a lowpower sleep (LPS) request, and ii) a wake-up request (WUR), and promptthe PHY processor to transmit the OAM frame to the second communicationdevice via the communication medium to signal to the secondcommunication device the one of i) the LPS request, and ii) the WUR.

Embodiment 2: The first communication device of embodiment 1, wherein:the controller is configured to generate the OAM frame to include aplurality of symbols; the PHY processor is configured to transmit theplurality of symbols in an order in time; and the controller is furtherconfigured to generate the OAM frame header to include the informationthat signals the one of i) the LPS request, and ii) the WUR within afirst symbol, among the plurality of symbols, that is transmitted firstin time among the plurality of symbols.

Embodiment 3: The first communication device of embodiment 2, wherein:the PHY processor is configured to transmit the plurality of symbols ina first order in time; and the controller is configured to generate thefirst symbol to include a plurality of bits; the PHY processor isconfigured to transmit the plurality of bits of the first symbol in asecond order in time; and the controller is configured to one of i) seta value of a first bit, among the plurality of bits, that is transmittedfifth in time among the plurality of bits to signal the LPS request, andii) set a value of a second bit, among the plurality of bits, that istransmitted sixth in time among the plurality of bits to signal the WUR.

Embodiment 4: The first communication device of embodiment 2, wherein:the PHY processor is configured to transmit the plurality of symbols ina first order in time; and the controller is configured to generate thefirst symbol to include a plurality of bits; the PHY processor isconfigured to transmit the plurality of bits of the first symbol in asecond order in time; and the controller is configured to one of i) seta value of a first bit, among the plurality of bits, that is transmittedfifth in time among the plurality of bits to signal the WUR, and ii) seta value of a second bit, among the plurality of bits, that istransmitted sixth in time among the plurality of bits to signal the LPSrequest.

Embodiment 5: The first communication device of embodiment 2, wherein:the controller is configured to generate the first symbol to include aplurality of bits arranged according to a bit order, the plurality ofbits including at least a first bit in the bit order, a second bit inthe bit order that is adjacent to and between the first bit and a thirdbit in the bit order, a fourth bit in the bit order that is adjacent toand between the third bit and a fifth bit in the bit order, a sixth bitin the bit order that is adjacent to and between the fifth bit and aseventh bit in the bit order, and an eighth bit in the bit order that isadjacent to the seventh bit; and the controller is configured to one ofi) set a value of the fifth bit in the bit order to signal the LPSrequest, and ii) set a value of the sixth bit in the bit order to signalthe WUR.

Embodiment 6: The first communication device of embodiment 2, wherein:the controller is configured to generate the first symbol to include aplurality of bits arranged according to a bit order, the plurality ofbits including at least a first bit in the bit order, a second bit inthe bit order that is adjacent to and between the first bit and a thirdbit in the bit order, a fourth bit in the bit order that is adjacent toand between the third bit and a fifth bit in the bit order, a sixth bitin the bit order that is adjacent to and between the fifth bit and aseventh bit in the bit order, and an eighth bit in the bit order that isadjacent to the seventh bit; and the controller is configured to one ofi) set a value of the fifth bit in the bit order to signal the WUR, andii) set a value of the sixth bit in the bit order to signal the LPSrequest.

Embodiment 7: The first communication device of any of embodiments 1-6,wherein the controller comprises: a processor; and a memory coupled tothe processor, the memory storing machine readable instructions that,when executed by the processor, cause the processor to: generate the OAMframe that includes i) the OAM message content and ii) the OAM frameheader.

Embodiment 8: The first communication device of any of embodiments 1-6,wherein the controller comprises: hardware circuitry configured togenerate the OAM frame that includes i) the OAM message content and ii)the OAM frame header.

Embodiment 9: A method for communicating in a communication network, themethod comprising: generating, at a first communication device, anOperation, Administration, and Maintenance (OAM) frame that includes i)OAM message content and ii) an OAM frame header outside of the OAMmessage content, wherein generating the OAM frame comprises generatingthe OAM frame header to include information that signals one of i) a lowpower sleep (LPS) request, and ii) a wake-up request (WUR); andtransmitting, by the first communication device, the OAM frame to asecond communication device via a communication medium to signal to thesecond communication device the one of i) the LPS request, and ii) theWUR.

Embodiment 10: The method for communicating of embodiment 9, wherein:generating the OAM frame comprises generating the OAM frame to include aplurality of symbols; transmitting the OAM frame comprises transmittingthe plurality of symbols in an order in time; and generating the OAMframe header to include the information that signals the one of i) theLPS request, and ii) the WUR within a first symbol, among the pluralityof symbols, that is transmitted first in time among the plurality ofsymbols.

Embodiment 11: The method for communicating of embodiment 10, wherein:transmitting the OAM frame comprises transmitting the plurality ofsymbols in a first order in time; and generating the OAM frame headercomprises generating the first symbol to include a plurality of bits;transmitting the OAM frame further comprises transmitting the pluralityof bits of the first symbol in a second order in time; and generatingthe OAM frame header to include the information that signals the one ofi) the LPS, and ii) the WUR within a first symbol comprises one of i)setting a value of a first bit, among the plurality of bits, that istransmitted fifth in time among the plurality of bits to signal the LPSrequest, and ii) setting a value of a second bit, among the plurality ofbits, that is transmitted sixth in time among the plurality of bits tosignal the WUR.

Embodiment 12: The method for communicating of embodiment 10, wherein:transmitting the OAM frame comprises transmitting the plurality ofsymbols in a first order in time; and generating the OAM frame headercomprises generating the first symbol to include a plurality of bits;transmitting the OAM frame further comprises transmitting the pluralityof bits of the first symbol in a second order in time; and generatingthe OAM frame header to include the information that signals the one ofi) the LPS, and ii) the WUR within a first symbol comprises one of i)setting a value of a first bit, among the plurality of bits, that istransmitted fifth in time among the plurality of bits to signal the WUR,and ii) setting a value of a second bit, among the plurality of bits,that is transmitted sixth in time among the plurality of bits to signalthe LPS request.

Embodiment 13: The method for communicating of embodiment 10, wherein:generating the OAM frame header comprises generating the first symbol toinclude a plurality of bits arranged according to a bit order, theplurality of bits including at least a first bit in the bit order, asecond bit in the bit order that is adjacent to and between the firstbit and a third bit in the bit order, a fourth bit in the bit order thatis adjacent to and between the third bit and a fifth bit in the bitorder, a sixth bit in the bit order that is adjacent to and between thefifth bit and a seventh bit in the bit order, and an eighth bit in thebit order that is adjacent to the seventh bit; and generating the OAMframe header to include the information that signals the one of i) theLPS, and ii) the WUR within a first symbol comprises one of i) setting avalue of the fifth bit in the bit order to signal the LPS request, andii) setting a value of the sixth bit in the bit order to signal the WUR.

Embodiment 14: The method for communicating of embodiment 10, wherein:generating the OAM frame header comprises generating the first symbol toinclude a plurality of bits arranged according to a bit order, theplurality of bits including at least a first bit in the bit order, asecond bit in the bit order that is adjacent to and between the firstbit and a third bit in the bit order, a fourth bit in the bit order thatis adjacent to and between the third bit and a fifth bit in the bitorder, a sixth bit in the bit order that is adjacent to and between thefifth bit and a seventh bit in the bit order, and an eighth bit in thebit order that is adjacent to the seventh bit; and generating the OAMframe header to include the information that signals the one of i) theLPS, and ii) the WUR within a first symbol comprises one of i) setting avalue of the fifth bit in the bit order to signal the WUR, and ii)setting a value of the sixth bit in the bit order to signal the LPSrequest.

Embodiment 15: A first communication device, comprising: a physicallayer (PHY) processor comprising a transceiver, the PHY processor beingconfigured to perform PHY functions associated with a communication linkincluding transmitting first frames to a second communication device viaa communication medium corresponding to the communication link andreceiving second frames from the second communication device via thecommunication medium; and a controller configured to: receive anOperation, Administration, and Maintenance (OAM) frame that was receivedby the PHY processor via the communication medium, the OAM frame havingbeen transmitted to the first communication device from a secondcommunication device via the communication medium, the OAM frameincluding i) OAM message content and ii) an OAM frame header outside ofthe OAM message content, and process the OAM frame header to determinewhether the OAM frame header includes information that signals to thefirst communication device one of i) a low power sleep (LPS) request,and ii) a wake-up request (WUR).

Embodiment 16: The first communication device of embodiment 15, wherein:the OAM frame includes a plurality of symbols; and the controller isfurther configured to process a first symbol, among the plurality ofsymbols, that was received by the PHY processor first in time among theplurality of symbols, to determine whether the first symbol includes theinformation that signals the one of i) the LPS request, and ii) the WUR.

Embodiment 17: The first communication device of embodiment 16, wherein:the first symbol includes a plurality of bits; and the controller isfurther configured to determine i) whether a value of a first bit, amongthe plurality of bits, that is received by the PHY processor fifth intime among the plurality of bits is set to signal the LPS request, andii) whether a value of a second bit, among the plurality of bits, thatis received by the PHY processor sixth in time among the plurality ofbits is set to signal the WUR.

Embodiment 18: The first communication device of embodiment 16, wherein:the first symbol includes a plurality of bits; and the controller isfurther configured to determine i) whether a value of a first bit, amongthe plurality of bits, that is transmitted fifth in time among theplurality of bits is set to signal the WUR request, and ii) whether avalue of a second bit, among the plurality of bits, that is transmittedsixth in time among the plurality of bits is set to signal the LPSrequest.

Embodiment 19: The first communication device of embodiment 16, wherein:the first symbol includes a plurality of bits arranged according to abit order, the plurality of bits including at least a first bit in thebit order, a second bit in the bit order that is adjacent to and betweenthe first bit and a third bit in the bit order, a fourth bit in the bitorder that is adjacent to and between the third bit and a fifth bit inthe bit order, a sixth bit in the bit order that is adjacent to andbetween the fifth bit and a seventh bit in the bit order, and an eighthbit in the bit order that is adjacent to the seventh bit; and thecontroller is further configured to determine i) whether a value of thefifth bit in the bit order is set to signal the LPS request, and ii)whether a value of the sixth bit in the bit order is set to signal theWUR.

Embodiment 20: The first communication device of embodiment 16, wherein:the first symbol includes a plurality of bits arranged according to abit order, the plurality of bits including at least a first bit in thebit order, a second bit in the bit order that is adjacent to and betweenthe first bit and a third bit in the bit order, a fourth bit in the bitorder that is adjacent to and between the third bit and a fifth bit inthe bit order, a sixth bit in the bit order that is adjacent to andbetween the fifth bit and a seventh bit in the bit order, and an eighthbit in the bit order that is adjacent to the seventh bit; and thecontroller is further configured to determine i) whether a value of thefifth bit in the bit order is set to signal the WUR request, and ii)whether a value of the sixth bit in the bit order is set to signal theLPS request.

Embodiment 21: The first communication device of any of embodiments15-20, wherein the controller comprises: a processor; and a memorycoupled to the processor, the memory storing machine readableinstructions that, when executed by the processor, cause the processorto: process the OAM frame header to determine whether the OAM frameheader includes the information that signals to the first communicationdevice the one of i) the LPS request, and ii) the WUR.

Embodiment 22: The first communication device of any of embodiments15-20, wherein the controller comprises: hardware circuitry configuredto process the OAM frame header to determine whether the OAM frameheader includes the information that signals to the first communicationdevice the one of i) the LPS request, and ii) the WUR.

Embodiment 23: A method for processing communications in a communicationnetwork, the method comprising: receiving, at a first communicationdevice, an Operation, Administration, and Maintenance (OAM) frame from asecond communication device via a communication medium, the OAM frameincluding i) OAM message content and ii) an OAM frame header outside ofthe OAM message content; and processing, at the first communicationdevice, the OAM frame header to determine whether the OAM frame headerincludes information that signals to the first communication device oneof i) a low power sleep (LPS) request, and ii) a wake-up request (WUR).

Embodiment 24: The method for processing communications of embodiment23, wherein: the OAM frame includes a plurality of symbols; andprocessing the OAM frame header comprises processing a first symbol,among the plurality of symbols, that was received by the firstcommunication device first in time among the plurality of symbols, todetermine whether the first symbol includes the information that signalsthe one of i) the LPS request, and ii) the WUR.

Embodiment 25: The method for processing communications of embodiment24, wherein: the first symbol includes a plurality of bits; andprocessing the OAM frame header comprises processing a first symbol,among the plurality of symbols, that was received by the firstcommunication device comprises determining i) whether a value of a firstbit, among the plurality of bits, that is received by the firstcommunication device fifth in time among the plurality of bits is set tosignal the LPS request, and ii) whether a value of a second bit, amongthe plurality of bits, that is received by the first communicationdevice sixth in time among the plurality of bits is set to signal theWUR.

Embodiment 26: The method for processing communications of embodiment24, wherein: the first symbol includes a plurality of bits; andprocessing the OAM frame header comprises processing a first symbol,among the plurality of symbols, that was received by the firstcommunication device comprises determining i) whether a value of a firstbit, among the plurality of bits, that is received by the firstcommunication device fifth in time among the plurality of bits is set tosignal the WUR, and ii) whether a value of a second bit, among theplurality of bits, that is received by the first communication devicesixth in time among the plurality of bits is set to signal the LPSrequest.

Embodiment 27: The method for processing communications of embodiment24, wherein: the first symbol includes a plurality of bits arrangedaccording to a bit order, the plurality of bits including at least afirst bit in the bit order, a second bit in the bit order that isadjacent to and between the first bit and a third bit in the bit order,a fourth bit in the bit order that is adjacent to and between the thirdbit and a fifth bit in the bit order, a sixth bit in the bit order thatis adjacent to and between the fifth bit and a seventh bit in the bitorder, and an eighth bit in the bit order that is adjacent to theseventh bit; and processing the OAM frame header comprises processing afirst symbol, among the plurality of symbols, that was received by thefirst communication device comprises determining i) whether a value ofthe fifth bit in the bit order is set to signal the LPS request, and ii)whether a value of the sixth bit in the bit order is set to signal theWUR.

Embodiment 28: The method for processing communications of embodiment24, wherein: the first symbol includes a plurality of bits arrangedaccording to a bit order, the plurality of bits including at least afirst bit in the bit order, a second bit in the bit order that isadjacent to and between the first bit and a third bit in the bit order,a fourth bit in the bit order that is adjacent to and between the thirdbit and a fifth bit in the bit order, a sixth bit in the bit order thatis adjacent to and between the fifth bit and a seventh bit in the bitorder, and an eighth bit in the bit order that is adjacent to theseventh bit; and processing the OAM frame header comprises processing afirst symbol, among the plurality of symbols, that was received by thefirst communication device comprises determining i) whether a value ofthe fifth bit in the bit order is set to signal the WUR, and ii) whethera value of the sixth bit in the bit order is set to signal the LPSrequest.

At least some of the various blocks, operations, and techniquesdescribed above may be implemented utilizing hardware, a processorexecuting firmware instructions, a processor executing softwareinstructions, or any combination thereof. When implemented utilizing aprocessor executing software or firmware instructions, the software orfirmware instructions may be stored in any computer readable memory suchas on a magnetic disk, an optical disk, or other storage medium, in aRAM or ROM or flash memory, processor, hard disk drive, optical diskdrive, tape drive, etc. The software or firmware instructions mayinclude machine readable instructions that, when executed by one or moreprocessors, cause the one or more processors to perform various acts.

When implemented in hardware, the hardware may comprise one or more ofdiscrete components, an integrated circuit, an application-specificintegrated circuit (ASIC), a programmable logic device (PLD), etc.

While the present invention has been described with reference tospecific examples, which are intended to be illustrative only and not tobe limiting of the invention, changes, additions and/or deletions may bemade to the disclosed embodiments without departing from the scope ofthe invention.

What is claimed is:
 1. A first communication device, comprising: aphysical layer (PHY) processor comprising a transceiver, the PHYprocessor being configured to perform PHY functions associated with acommunication link including transmitting first frames to a secondcommunication device via a communication medium corresponding to thecommunication link and receiving second frames from the secondcommunication device via the communication medium; and a controllerconfigured to: generate an Operation, Administration, and Maintenance(OAM) frame that includes a plurality of symbols, and that includes i)OAM message content among the plurality of symbols and ii) an OAM frameheader outside of the OAM message content, the OAM frame headerincluding a first symbol and a second symbol among the plurality ofsymbols, the second symbol comprising a set of bits that indicates ameaning of the OAM message content, wherein generating the OAM framecomprises generating the first symbol of the OAM frame header to includea plurality of bits arranged according to a bit order, the plurality ofbits including at least a first bit in the bit order, a second bit inthe bit order that is adjacent to and between the first bit and a thirdbit in the bit order, a fourth bit in the bit order that is adjacent toand between the third bit and a fifth bit in the bit order, a sixth bitin the bit order that is adjacent to and between the fifth bit and aseventh bit in the bit order, and an eighth bit in the bit order that isadjacent to the seventh bit, one of i) set a value of the fifth bit inthe bit order to signal a low power sleep (LPS) request, and ii) set avalue of the sixth bit in the bit order to signal a wake-up request(WUR), and prompt the PHY processor to transmit the OAM frame to thesecond communication device via the communication medium to signal tothe second communication device the one of i) the LPS request, and ii)the WUR, including prompting the PHY processor to transmit the OAM frameso that the first symbol is transmitted first in time among theplurality of symbols.
 2. The first communication device of claim 1,wherein the controller comprises: a processor; and a memory coupled tothe processor, the memory storing machine readable instructions that,when executed by the processor, cause the processor to: generate the OAMframe that includes i) the OAM message content and ii) the OAM frameheader.
 3. The first communication device of claim 1, wherein thecontroller comprises: hardware circuitry configured to generate the OAMframe that includes i) the OAM message content and ii) the OAM frameheader.
 4. A method for communicating in a communication network, themethod comprising: generating, at a first communication device, anOperation, Administration, and Maintenance (OAM) frame that includes aplurality of symbols, and that includes i) OAM message content among theplurality of symbols and ii) an OAM frame header outside of the OAMmessage content, the OAM frame header including a first symbol and asecond symbol among the plurality of symbols, the second symbolcomprising a set of bits that indicates a meaning of the OAM messagecontent, wherein generating the OAM frame comprises generating the firstsymbol of the OAM frame header to include a plurality of bits arrangedaccording to a bit order, the plurality of bits including at least afirst bit in the bit order, a second bit in the bit order that isadjacent to and between the first bit and third bit in the bit order, afourth bit in the bit order that is adjacent to and between the thirdbit and a fifth bit in the bit order, a sixth bit in the bit order thatis adjacent to and between the fifth bit and a seventh bit in the bitorder, and an eighth bit in the bit order that is adjacent to theseventh bit; one of i) setting a value of the fifth bit in the bit orderto signal a low power sleep (LPS) request, and ii) setting a value ofthe sixth bit in the bit order to signal a wake-up request (WUR); andtransmitting, by the first communication device, the OAM frame to asecond communication device via a communication medium to signal to thesecond communication device the one of i) the LPS request, and ii) theWUR, including transmitting the first symbol first in time among theplurality of symbols.
 5. A first communication device, comprising: aphysical layer (PHY) processor comprising a transceiver, the PHYprocessor being configured to perform PHY functions associated with acommunication link including transmitting first frames to a secondcommunication device via a communication medium corresponding to thecommunication link and receiving second frames from the secondcommunication device via the communication medium; and a controllerconfigured to: receive an Operation, Administration, and Maintenance(OAM) frame that was received by the PHY processor via the communicationmedium, the OAM frame having been transmitted to the first communicationdevice from a second communication device via the communication medium,the OAM frame including a plurality of symbols, and further including i)OAM message content among the plurality of symbols and ii) an OAM frameheader outside of the OAM message content, the OAM frame headerincluding a first symbol and a second symbol among the plurality ofsymbols, the second symbol comprising a set of bits that indicates ameaning of the OAM message content, wherein the first symbol is receivedby the PHY processor first in time among the plurality of symbols, andwherein the first symbol includes a plurality of bits arranged accordingto a bit order, the plurality of bits including at least a first bit inthe bit order, a second bit in the bit order that is adjacent to andbetween the first bit and a third bit in the bit order, a fourth bit inthe bit order that is adjacent to and between the third bit and a fifthbit in the bit order, a sixth bit in the bit order that is adjacent toand between the fifth bit and a seventh bit in the bit order, and aneighth bit in the bit order that is adjacent to the seventh bit, andprocess the first symbol of the OAM frame header to determine one of i)whether a value of the fifth bit in the bit order is set to signal a lowpower sleep (LPS) request, and ii) whether a value of the sixth bit inthe bit order is set to signal a wake-up request (WUR).
 6. The firstcommunication device of claim 5, wherein the controller comprises: aprocessor; and a memory coupled to the processor, the memory storingmachine readable instructions that, when executed by the processor,cause the processor to: process the first symbol of the OAM frame headerto determine the one of i) whether the value of the fifth bit in the bitorder is set to signal the LPS request, and ii) whether the value of thesixth bit in the bit order is set to signal the WUR.
 7. The firstcommunication device of claim 5, wherein the controller comprises:hardware circuitry configured to process the first symbol of the OAMframe header to determine the one of i) whether the value of the fifthbit in the bit order is set to signal the LPS request, and ii) whetherthe value of the sixth bit in the bit order is set to signal the WUR. 8.A method for processing communications in a communication network, themethod comprising: receiving, at a first communication device, anOperation, Administration, and Maintenance (OAM) frame from a secondcommunication device via a communication medium, the OAM frame includinga plurality of symbols, and including i) OAM message content among theplurality of symbols and ii) an OAM frame header outside of the OAMmessage content, the OAM frame header including a first symbol and asecond symbol among the plurality of symbols, the second symbolcomprising a set of bits that indicates a meaning of the OAM messagecontent, wherein receiving the OAM frame comprises receiving the firstsymbol first in time among the plurality of symbols, and the firstsymbol including a plurality of bits arranged according to a bit order,the plurality of bits including at least a first bit in the bit order, asecond bit in the bit order that is adjacent to and between the firstbit and a third bit in the bit order, a fourth bit in the bit order thatis adjacent to and between the third bit and a fifth bit in the bitorder, a sixth bit in the bit order that is adjacent to and between thefifth bit and a seventh bit in the bit order, and an eighth bit in thebit order that is adjacent to the seventh bit; and processing, at thefirst communication device, the first symbol of the OAM frame header todetermine one of i) whether a value of the fifth bit in the bit order isset to signal a low power sleep (LPS) request, and ii) whether a valueof the sixth bit in the bit order is set to signal a wake-up request(WUR).